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Robinson JM, Barnes AD, Fickling N, Costin S, Sun X, Breed MF. Food webs in food webs: the micro-macro interplay of multilayered networks. Trends Ecol Evol 2024:S0169-5347(24)00144-7. [PMID: 38960756 DOI: 10.1016/j.tree.2024.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 06/10/2024] [Accepted: 06/14/2024] [Indexed: 07/05/2024]
Abstract
Food webs are typically defined as being macro-organism-based (e.g., plants, mammals, birds) or microbial (e.g., bacteria, fungi, viruses). However, these characterizations have limits. We propose a multilayered food web conceptual model where microbial food webs are nested within food webs composed of macro-organisms. Nesting occurs through host-microbe interactions, which influence the health and behavior of host macro-organisms, such that host microbiomes likely alter population dynamics of interacting macro-organisms and vice versa. Here, we explore the theoretical underpinnings of multilayered food webs and the implications of this new conceptual model on food web ecology. Our framework opens avenues for new empirical investigations into complex ecological networks and provides a new lens through which to view a network's response to ecosystem changes.
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Affiliation(s)
- Jake M Robinson
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia; The Aerobiome Innovation and Research Hub, College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia.
| | - Andrew D Barnes
- School of Science, University of Waikato, Hamilton, New Zealand
| | - Nicole Fickling
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia; The Aerobiome Innovation and Research Hub, College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
| | - Sofie Costin
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
| | - Xin Sun
- The Aerobiome Innovation and Research Hub, College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia; Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Fujian Key Laboratory of Watershed Ecology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, China.
| | - Martin F Breed
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia; The Aerobiome Innovation and Research Hub, College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia.
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2
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Chang W, Zhang P, Li J, Aspe NM, Hao J, Lu S, Wan Z, Wu D. Impacts of Millipedes on Acari and Collembola Communities-A Microcosm Experiment. INSECTS 2024; 15:456. [PMID: 38921170 PMCID: PMC11203639 DOI: 10.3390/insects15060456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 05/23/2024] [Accepted: 06/10/2024] [Indexed: 06/27/2024]
Abstract
Ecosystem engineers influence the structure and function of soil food webs through non-trophic interactions. The activity of large soil animals, such as earthworms, has a significant impact on the soil microarthropod community. However, the influence of millipedes on soil microarthropod communities remains largely unknown. In this microcosm experiment, we examined the effects of adding, removing, and restricting millipede activity on Acari and Collembola communities in litter and soil by conducting two destructive sampling sessions on days 10 and 30, respectively. At the time of the first sampling event (10 d), Acari and Collembola abundance was shown to increase and the alpha diversity went higher in the treatments with millipedes. At the time of the second sampling event (30 d), millipedes significantly reduced the Collembola abundance and alpha diversity. The results were even more pronounced as the millipedes moved through the soil, which caused the collembolans to be more inclined to inhabit the litter, which in turn resulted in the increase in the abundance and diversity of Acari in the soil. The rapid growth of Collembola in the absence of millipedes significantly inhibited the abundance of Acari. The presence of millipedes altered the community structure of Acari and Collembola, leading to a stronger correlation between the two communities. Changes in these communities were driven by the dominant taxa of Acari and Collembola. These findings suggest that millipedes, as key ecosystem engineers, have varying impacts on different soil microarthropods. This study enhances our understanding of biological interactions and offers a theoretical foundation for soil biodiversity conservation.
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Affiliation(s)
- Wenjin Chang
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China; (W.C.); (J.L.); (J.H.); (S.L.); (Z.W.)
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China;
| | - Peng Zhang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China;
| | - Jianwei Li
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China; (W.C.); (J.L.); (J.H.); (S.L.); (Z.W.)
| | - Nonillon M. Aspe
- College of Marine and Allied Sciences, Mindanao State University at Naawan, Naawan 9023, Misamis Oriental, Philippines;
| | - Jiahua Hao
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China; (W.C.); (J.L.); (J.H.); (S.L.); (Z.W.)
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China;
| | - Siyuan Lu
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China; (W.C.); (J.L.); (J.H.); (S.L.); (Z.W.)
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China;
| | - Zhuoma Wan
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China; (W.C.); (J.L.); (J.H.); (S.L.); (Z.W.)
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China;
| | - Donghui Wu
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China; (W.C.); (J.L.); (J.H.); (S.L.); (Z.W.)
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China;
- Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun 130024, China
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China
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3
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Aguadé-Gorgorió G, Anderson AR, Solé R. Modeling tumors as species-rich ecological communities. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.22.590504. [PMID: 38712062 PMCID: PMC11071393 DOI: 10.1101/2024.04.22.590504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Many advanced cancers resist therapeutic intervention. This process is fundamentally related to intra-tumor heterogeneity: multiple cell populations, each with different mutational and phenotypic signatures, coexist within a tumor and its metastatic nodes. Like species in an ecosystem, many cancer cell populations are intertwined in a complex network of ecological interactions. Most mathematical models of tumor ecology, however, cannot account for such phenotypic diversity nor are able to predict its consequences. Here we propose that the Generalized Lotka-Volterra model (GLV), a standard tool to describe complex, species-rich ecological communities, provides a suitable framework to describe the ecology of heterogeneous tumors. We develop a GLV model of tumor growth and discuss how its emerging properties, such as outgrowth and multistability, provide a new understanding of the disease. Additionally, we discuss potential extensions of the model and their application to three active areas of cancer research, namely phenotypic plasticity, the cancer-immune interplay and the resistance of metastatic tumors to treatment. Our work outlines a set of questions and a tentative road map for further research in cancer ecology.
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Affiliation(s)
| | - Alexander R.A. Anderson
- Integrated Mathematical Oncology Department, H. Lee Moffitt Cancer Center & Research Institute, Tampa, USA
| | - Ricard Solé
- ICREA-Complex Systems Lab, UPF-PRBB, Dr. Aiguader 80, 08003 Barcelona, Spain
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
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4
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Hoang KL, Salguero-Gómez R, Pike VL, King KC. The impacts of host association and perturbation on symbiont fitness. Symbiosis 2024; 92:439-451. [PMID: 38666134 PMCID: PMC11039428 DOI: 10.1007/s13199-024-00984-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 03/04/2024] [Indexed: 04/28/2024]
Abstract
Symbiosis can benefit hosts in numerous ways, but less is known about whether interactions with hosts benefit symbionts-the smaller species in the relationship. To determine the fitness impact of host association on symbionts in likely mutualisms, we conducted a meta-analysis across 91 unique host-symbiont pairings under a range of spatial and temporal contexts. Specifically, we assess the consequences to symbiont fitness when in and out of symbiosis, as well as when the symbiosis is under suboptimal or varying environments and biological conditions (e.g., host age). We find that some intracellular symbionts associated with protists tend to have greater fitness when the symbiosis is under stressful conditions. Symbionts of plants and animals did not exhibit this trend, suggesting that symbionts of multicellular hosts are more robust to perturbations. Symbiont fitness also generally increased with host age. Lastly, we show that symbionts able to proliferate in- and outside host cells exhibit greater fitness than those found exclusively inside or outside cells. The ability to grow in multiple locations may thus help symbionts thrive. We discuss these fitness patterns in light of host-driven factors, whereby hosts exert influence over symbionts to suit their own needs. Supplementary Information The online version contains supplementary material available at 10.1007/s13199-024-00984-6.
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Affiliation(s)
- Kim L. Hoang
- Department of Biology, University of Oxford, Oxford, UK
- Emory University School of Medicine, Atlanta, GA USA
| | | | | | - Kayla C. King
- Department of Biology, University of Oxford, Oxford, UK
- Department of Zoology, University of British Columbia, Vancouver, Canada
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, Canada
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5
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Zwolak R, Clement D, Sih A, Schreiber SJ. Granivore abundance shapes mutualism quality in plant-scatterhoarder interactions. THE NEW PHYTOLOGIST 2024; 241:1840-1850. [PMID: 38044708 DOI: 10.1111/nph.19443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/08/2023] [Indexed: 12/05/2023]
Abstract
Conditional mutualisms involve costs and benefits that vary with environmental factors, but mechanisms driving these dynamics remain poorly understood. Scatterhoarder-plant interactions are a prime example of this phenomenon, as scatterhoarders can either increase or reduce plant recruitment depending on the balance between seed dispersal and predation. We explored factors that drive the magnitude of net benefits for plants in this interaction using a mathematical model, with parameter values based on European beech (Fagus sylvatica) and yellow-necked mice (Apodemus flavicollis). We measured benefits as the percentage of germinating seeds, and examined how varying rodent survival (reflecting, e.g. changes in predation pressure), the rate of seed loss to other granivores, the abundance of alternative food resources, and changes in masting patterns affect the quality of mutualism. We found that increasing granivore abundance can degrade the quality of plant-scatterhoarder mutualism due to increased cache pilferage. Scatterhoarders are predicted to respond by increasing immediate consumption of gathered seeds, leading to higher costs and reduced benefits for plants. Thus, biotic changes that are detrimental to rodent populations can be beneficial for tree recruitment due to adaptive behavior of rodents. When scatterhoarder populations decline too drastically (< 5 individuals ha-1 ); however, tree recruitment may also suffer.
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Affiliation(s)
- Rafał Zwolak
- Department of Systematic Zoology, Institute of Environmental Biology, Adam Mickiewicz University, Umultowska 89, Poznań, 61-614, Poland
| | - Dale Clement
- School of Biological Sciences, Washington State University, Pullman, WA, 99164-4236, USA
| | - Andrew Sih
- Center of Population Biology, University of California, One Shields Avenue, Davis, CA, 95616, USA
| | - Sebastian J Schreiber
- Center of Population Biology, University of California, One Shields Avenue, Davis, CA, 95616, USA
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6
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Pedraza F, Liu H, Gawecka KA, Bascompte J. The Role of Indirect Effects in Coevolution along the Mutualism-Antagonism Continuum. Am Nat 2024; 203:28-42. [PMID: 38207144 DOI: 10.1086/727472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
AbstractThe web of interactions in a community drives the coevolution of species. Yet it is unclear how the outcome of species interactions influences the coevolutionary dynamics of communities. This is a pressing matter, as changes to the outcome of interactions may become more common with human-induced global change. Here, we combine network and evolutionary theory to explore coevolutionary outcomes in communities harboring mutualistic and antagonistic interactions. We show that as the ratio of mutualistic to antagonistic interactions decreases, selection imposed by direct partners outweighs that imposed by indirect partners. This weakening of indirect effects results in communities composed of species with dissimilar traits and fast rates of adaptation. These changes are more pronounced when specialist consumers are the first species to engage in antagonistic interactions. Hence, a shift in the outcome of species interactions may reverberate across communities and alter the direction and speed of coevolution.
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7
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Capelle JJ, Hartog E, Wilkes T, Bouma TJ. Seasonal variation in the balance and strength of cooperative and competitive behavior in patches of blue mussels. PLoS One 2023; 18:e0293142. [PMID: 37856481 PMCID: PMC10586602 DOI: 10.1371/journal.pone.0293142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 10/05/2023] [Indexed: 10/21/2023] Open
Abstract
Aggregation into groups may affect performance of individuals through the balance and strength of facilitative versus competitive interactions. We studied in situ how seasonal variation in abiotic environment affects this balance for blue mussels, a semi-sessile species. We hypothesize that seasonal variation in stresses and resources affects the strength of the interaction. We expected that, in benign conditions (here: high food availability, medium temperatures, low hydrodynamic stress), performance is dominated by growth and is better at low densities, while at adverse conditions (here: low food availability, low or high temperatures, high hydrodynamic stress), performance is dominated by survival and higher at high densities. Mussels were kept in shallow subtidal exclosures at 10 different densities for a one-month period. This exact procedure was repeated seven times at the same location within a one-year period. We measured development in mussel patch shape, performance, and environmental parameters. Environmental conditions for mussels were most benign in summer and most adverse in winter. Patches developed into less complex shapes at lower densities, but also after stronger hydrodynamic disturbances. Towards summer, mussels became more active, aggregation behavior increased, and interactions became more pronounced. Towards winter, mussels became less active: aggregation behavior and growth rates declined and at the lowest temperatures survival started to decrease with mussel density. Survival and growth (by proxy of mussel condition) were both density-dependent; however, contrary to our expectations we found positive interactions between density and survival at the most benign conditions in summer and negative interactions at the most adverse conditions in winter. In between the two seasons, the strength of the interactions increased towards summer and decreased towards winter following a bell-shaped pattern. This pattern might be explained by the environmental mediated aggregation behavior of the mussels. The obvious seasonal pattern in balance and strength of density-dependent interactions demonstrates that strength and direction of intra-specific interactions are both strongly affected by environmental context.
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Affiliation(s)
- Jacob J. Capelle
- Wageningen University & Research -Wageningen Marine Research, Yerseke, The Netherlands
| | - Eva Hartog
- HZ University of Applied Sciences, Vlissingen, The Netherlands
| | - Tony Wilkes
- Wageningen University & Research -Wageningen Marine Research, Yerseke, The Netherlands
| | - Tjeerd J. Bouma
- Netherlands Institute for Sea Research, Yerseke, The Netherlands
- Faculty of Geosciences, Department of Physical Geography, Utrecht University, Utrecht, The Netherlands
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8
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Allen-Perkins A, García-Callejas D, Bartomeus I, Godoy O. Structural asymmetry in biotic interactions as a tool to understand and predict ecological persistence. Ecol Lett 2023; 26:1647-1662. [PMID: 37515408 DOI: 10.1111/ele.14291] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 06/29/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023]
Abstract
A universal feature of ecological systems is that species do not interact with others with the same sign and strength. Yet, the consequences of this asymmetry in biotic interactions for the short- and long-term persistence of individual species and entire communities remains unclear. Here, we develop a set of metrics to evaluate how asymmetric interactions among species translate to asymmetries in their individual vulnerability to extinction under changing environmental conditions. These metrics, which solve previous limitations of how to independently quantify the size from the shape of the so-called feasibility domain, provide rigorous advances to understand simultaneously why some species and communities present more opportunities to persist than others. We further demonstrate that our shape-related metrics are useful to predict short-term changes in species' relative abundances during 7 years in a Mediterranean grassland. Our approach is designed to be applied to any ecological system regardless of the number of species and type of interactions. With it, we show that is possible to obtain both mechanistic and predictive information on ecological persistence for individual species and entire communities, paving the way for a stronger integration of theoretical and empirical research.
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Affiliation(s)
- Alfonso Allen-Perkins
- Departamento de Ingeniería Eléctrica, Electrónica, Automática y Física Aplicada, ETSIDI, Technical University of Madrid, Madrid, Spain
| | - David García-Callejas
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Landcare Research, Lincoln, New Zealand
| | | | - Oscar Godoy
- Departamento de Biología, Instituto Universitario de Ciencias del Mar (INMAR), Universidad de Cádiz, Puerto Real, Spain
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9
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Song C, Simmons BI, Fortin MJ, Gonzalez A, Kaiser-Bunbury CN, Saavedra S. Rapid monitoring of ecological persistence. Proc Natl Acad Sci U S A 2023; 120:e2211288120. [PMID: 37155860 PMCID: PMC10194002 DOI: 10.1073/pnas.2211288120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 03/29/2023] [Indexed: 05/10/2023] Open
Abstract
Effective conservation of ecological communities requires accurate and up-to-date information about whether species are persisting or declining to extinction. The persistence of an ecological community is supported by its underlying network of species interactions. While the persistence of the network supporting the whole community is the most relevant scale for conservation, in practice, only small subsets of these networks can be monitored. There is therefore an urgent need to establish links between the small snapshots of data conservationists can collect, and the "big picture" conclusions about ecosystem health demanded by policymakers, scientists, and societies. Here, we show that the persistence of small subnetworks (motifs) in isolation-that is, their persistence when considered separately from the larger network of which they are a part-is a reliable probabilistic indicator of the persistence of the network as a whole. Our methods show that it is easier to detect if an ecological community is not persistent than if it is persistent, allowing for rapid detection of extinction risk in endangered systems. Our results also justify the common practice of predicting ecological persistence from incomplete surveys by simulating the population dynamics of sampled subnetworks. Empirically, we show that our theoretical predictions are supported by data on invaded networks in restored and unrestored areas, even in the presence of environmental variability. Our work suggests that coordinated action to aggregate information from incomplete sampling can provide a means to rapidly assess the persistence of entire ecological networks and the expected success of restoration strategies.
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Affiliation(s)
- Chuliang Song
- Department of Biology, Quebec Centre for Biodiversity Science, McGill University, Montreal, QCH3A 0G4, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ONM5S 3B2, Canada
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ08544
| | - Benno I. Simmons
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, PenrynTR10 9FE, United Kingdom
| | - Marie-Josée Fortin
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ONM5S 3B2, Canada
| | - Andrew Gonzalez
- Department of Biology, Quebec Centre for Biodiversity Science, McGill University, Montreal, QCH3A 0G4, Canada
| | | | - Serguei Saavedra
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA02138
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Evans LC, Greenwell MP, Boult VL, Johnson TF. Characterizing the trophy hunting debate on Twitter. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2023:e14070. [PMID: 36890651 DOI: 10.1111/cobi.14070] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 01/20/2023] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Social media is an arena of debate for contentious political and social topics. One conservation topic debated online is the acceptability of trophy hunting, a debate that has implications for national and international policy. We used a mixed-methods approach (grounded theory and quantitative clustering) to identify themes in the trophy hunting debate on Twitter. We examined commonly co-occurring categories that describe people's stances on trophy hunting. We identified 12 categories and 4 preliminary archetypes opposing trophy hunting-activism, scientific, condemning, and objecting-whose opposition derived from different moral reasoning. Few tweets (22) in our sample of 500 supported trophy hunting, whereas 350 opposed it. The debate was hostile; 7% of tweets in our sample were categorized as abusive. Online debates can be unproductive, and our findings may be important for stakeholders wishing to effectively engage in the trophy hunting debate on Twitter. More generally, we contend that because social media is increasingly influential, it is important to formally contextualize public responses to contentious conservation topics in order to aid communication of conservation evidence and to integrate diverse public perspectives in conservation practice.
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Affiliation(s)
| | | | - Victoria L Boult
- National Centre for Atmospheric Sciences, Reading, UK
- Department of Meteorology, University of Reading, Reading, UK
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11
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Rosenfeld J, Gonzalez-Espinosa P, Jarvis L, Enders E, Bayly M, Paul A, MacPherson L, Moore J, Sullivan M, Ulaski M, Wilson K. Stressor-response functions as a generalizable model for context dependence. Trends Ecol Evol 2022; 37:1032-1035. [PMID: 36244864 DOI: 10.1016/j.tree.2022.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 09/14/2022] [Accepted: 09/20/2022] [Indexed: 11/07/2022]
Abstract
Defining the context dependence of ecological states or processes is a fundamental goal of ecology. Stressor-response functions are the quantitative representation of context dependence, where the context (environmental contingency) is defined by location on the stressor (x) axis, and represents a unifying concept in biological science.
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Affiliation(s)
- Jordan Rosenfeld
- UBC Institute for the Oceans and Fisheries, 2202 Main Mall, Vancouver, BC, Canada V6T 1Z4; BC Ministry of Environment, Vancouver, B.C., Canada.
| | | | - Lauren Jarvis
- Canada Department of Fisheries and Oceans, Freshwater Institute, Winnipeg, Canada, R3T 2N6
| | - Eva Enders
- Institute National de la Recherche Scientifique, Centre Eau Terre Environnement, Québec, Canada, G1K 9A9
| | | | - Andrew Paul
- Office of the Chief Scientist, Edmonton, Alberta, Canada, T6H 4P2
| | - Laura MacPherson
- Alberta Environment and Parks, Edmonton, Alberta, Canada T6H 4P2
| | - Jonathan Moore
- Department of Biological Sciences, Simon Fraser University, Vancouver, BC, Canada, V5A 1S6
| | - Michael Sullivan
- Alberta Environment and Parks, Edmonton, Alberta, Canada T6H 4P2
| | - Marta Ulaski
- Department of Biological Sciences, Simon Fraser University, Vancouver, BC, Canada, V5A 1S6
| | - Kyle Wilson
- Central Coast Indigenous Resource Alliance, Campbell River, BC, Canada, V9A 4X1
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12
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Remeš V, Harmáčková L, Matysioková B, Rubáčová L, Remešová E. Vegetation complexity and pool size predict species richness of forest birds. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.964180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Disentangling regional and local drivers of species richness in communities is a long-term focus of ecology. Regional species pools affect local communities by providing their constituent species. Additionally, the amount and variety of resources enhance diversity locally. Here, we investigated whether the same ecological factor (vegetation complexity) shapes both regional and local species richness and thus drives local diversity both indirectly (via pool size) and directly (via facilitating the coexistence of species). We studied passerine birds of woodlands and forests in eastern Australia. We quantified regional species pool size and sampled local bird communities at 63 transects spanning 3,000 km. We estimated canopy height both regionally using satellite imagery and locally using vegetation sampling in the field. We studied how species pool size changed with regional canopy height and water availability, and how local species richness changed with pool size and local canopy height. Local species richness increased with both local canopy height and the size of the regional species pool. Pool size, in turn, increased with regional canopy height, which itself increased with water availability. Moreover, local species richness expressed as a proportion of the regional pool also increased with local canopy height. In sum, vegetation complexity indexed by canopy height had a doubly positive effect on local species richness: indirectly by promoting a large regional species pool and directly by facilitating the coexistence of disproportionately many species locally. Regional pools were larger in tall forests probably due to the legacy of extensive moist forests that once covered most of Australia, thus providing a sizeable potential for speciation, diversification, and species persistence. Local species richness was greater in tall, more productive forests with more vegetation layers likely due to more and varied resources (i.e., more potential niches), allowing the coexistence of more individuals and species of consumers.
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13
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Pardikes NA, Revilla TA, Lue CH, Thierry M, Souto-Vilarós D, Hrcek J. Effects of phenological mismatch under warming are modified by community context. GLOBAL CHANGE BIOLOGY 2022; 28:4013-4026. [PMID: 35426203 DOI: 10.1111/gcb.16195] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
Climate change is altering the relative timing of species interactions by shifting when species first appear in communities and modifying the duration organisms spend in each developmental stage. However, community contexts, such as intraspecific competition and alternative resource species, can prolong shortened windows of availability and may mitigate the effects of phenological shifts on species interactions. Using a combination of laboratory experiments and dynamic simulations, we quantified how the effects of phenological shifts in Drosophila-parasitoid interactions differed with concurrent changes in temperature, intraspecific competition, and the presence of alternative host species. Our study confirmed that warming shortens the window of host susceptibility. However, the presence of alternative host species sustained interaction persistence across a broader range of phenological shifts than pairwise interactions by increasing the degree of temporal overlap with suitable development stages between hosts and parasitoids. Irrespective of phenological shifts, parasitism rates declined under warming due to reduced parasitoid performance, which limited the ability of community context to manage temporally mismatched interactions. These results demonstrate that the ongoing decline in insect diversity may exacerbate the effects of phenological shifts in ecological communities under future global warming temperatures.
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Affiliation(s)
- Nicholas A Pardikes
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Ceske Budejovice, Czech Republic
- Department of Life and Earth Sciences, Georgia State University-Perimeter College, Clarkston, Georgia, USA
| | - Tomás A Revilla
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Ceske Budejovice, Czech Republic
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Chia-Hua Lue
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Ceske Budejovice, Czech Republic
- Biology Department, Brooklyn College, City University of New York (CUNY), Brooklyn, New York, USA
| | - Melanie Thierry
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Ceske Budejovice, Czech Republic
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Daniel Souto-Vilarós
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Ceske Budejovice, Czech Republic
| | - Jan Hrcek
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Ceske Budejovice, Czech Republic
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
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14
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Thierry M, Pardikes NA, Rosenbaum B, Ximénez-Embún MG, Hrček J. The presence of multiple parasitoids decreases host survival under warming, but parasitoid performance also decreases. Proc Biol Sci 2022; 289:20220121. [PMID: 35291840 PMCID: PMC8924747 DOI: 10.1098/rspb.2022.0121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Current global changes are reshaping ecological communities and modifying environmental conditions. We need to recognize the combined impact of these biotic and abiotic factors on species interactions, community dynamics and ecosystem functioning. Specifically, the strength of predator-prey interactions often depends on the presence of other natural enemies: it weakens with competition and interference or strengthens with facilitation. Such effects of multiple predators on prey are likely to be affected by changes in the abiotic environment, altering top-down control, a key structuring force in natural and agricultural ecosystems. Here, we investigated how warming alters the effects of multiple predators on prey suppression using a dynamic model coupled with empirical laboratory experiments with Drosophila-parasitoid communities. While multiple parasitoids enhanced top-down control under warming, parasitoid performance generally declined when another parasitoid was present owing to competitive interactions. This could reduce top-down control over multiple generations. Our study highlights the importance of accounting for interactive effects between abiotic and biotic factors to better predict community dynamics in a rapidly changing world and thus better preserve ecosystem functioning and services such as biological control.
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Affiliation(s)
- Mélanie Thierry
- Faculty of Science, University of South Bohemia, Branisovska 31, 37005 Czech Republic,Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 37005, Czech Republic
| | - Nicholas A. Pardikes
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 37005, Czech Republic
| | - Benjamin Rosenbaum
- Theory in Biodiversity Science, German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Puschstr. 4, 04103 Leipzig, Germany,Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Str. 159, 07743 Jena, Germany
| | - Miguel G. Ximénez-Embún
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 37005, Czech Republic
| | - Jan Hrček
- Faculty of Science, University of South Bohemia, Branisovska 31, 37005 Czech Republic,Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 37005, Czech Republic
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15
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Addressing context dependence in ecology. Trends Ecol Evol 2021; 37:158-170. [PMID: 34756764 DOI: 10.1016/j.tree.2021.09.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 09/05/2021] [Accepted: 09/21/2021] [Indexed: 12/26/2022]
Abstract
Context dependence is widely invoked to explain disparate results in ecology. It arises when the magnitude or sign of a relationship varies due to the conditions under which it is observed. Such variation, especially when unexplained, can lead to spurious or seemingly contradictory conclusions, which can limit understanding and our ability to transfer findings across studies, space, and time. Using examples from biological invasions, we identify two types of context dependence resulting from four sources: mechanistic context dependence arises from interaction effects; and apparent context dependence can arise from the presence of confounding factors, problems of statistical inference, and methodological differences among studies. Addressing context dependence is a critical challenge in ecology, essential for increased understanding and prediction.
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16
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García-Callejas D, Bartomeus I, Godoy O. The spatial configuration of biotic interactions shapes coexistence-area relationships in an annual plant community. Nat Commun 2021; 12:6192. [PMID: 34702825 PMCID: PMC8548393 DOI: 10.1038/s41467-021-26487-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 09/24/2021] [Indexed: 11/18/2022] Open
Abstract
The increase of species richness with area is a universal phenomenon on Earth. However, this observation contrasts with our poor understanding of how these species-area relationships (SARs) emerge from the collective effects of area, spatial heterogeneity, and local interactions. By combining a structuralist approach with five years of empirical observations in a highly-diverse Mediterranean grassland, we show that spatial heterogeneity plays a little role in the accumulation of species richness with area in our system. Instead, as we increase the sampled area more species combinations are realized, and they coexist mainly due to direct pairwise interactions rather than by changes in single-species dominance or by indirect interactions. We also identify a small set of transient species with small population sizes that are consistently found across spatial scales. These findings empirically support the importance of the architecture of species interactions together with stochastic events for driving coexistence- and species-area relationships.
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Affiliation(s)
- David García-Callejas
- Estación Biológica de Doñana, C/Américo Vespucio 26, 41092, Seville, Spain.
- Departamento de Biología, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, E-11510, Puerto Real, Spain.
| | - Ignasi Bartomeus
- Estación Biológica de Doñana, C/Américo Vespucio 26, 41092, Seville, Spain
| | - Oscar Godoy
- Departamento de Biología, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, E-11510, Puerto Real, Spain
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17
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Song C, Uricchio LH, Mordecai EA, Saavedra S. Understanding the emergence of contingent and deterministic exclusion in multispecies communities. Ecol Lett 2021; 24:2155-2168. [PMID: 34288350 DOI: 10.1111/ele.13846] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/21/2021] [Accepted: 06/23/2021] [Indexed: 12/11/2022]
Abstract
Competitive exclusion can be classified as deterministic or as historically contingent. While competitive exclusion is common in nature, it has remained unclear when multispecies communities formed by more than two species should be dominated by deterministic or contingent exclusion. Here, we take a fully parameterised model of an empirical competitive system between invasive annual and native perennial plant species to explain both the emergence and sources of competitive exclusion in multispecies communities. Using a structural approach to understand the range of parameters promoting deterministic and contingent exclusions, we then find heuristic theoretical support for the following three general conclusions. First, we find that the life-history of perennial species increases the probability of observing contingent exclusion by increasing their effective intrinsic growth rates. Second, we find that the probability of observing contingent exclusion increases with weaker intraspecific competition, and not with the level of hierarchical competition. Third, we find a shift from contingent exclusion to deterministic exclusion with increasing numbers of competing species. Our work provides a heuristic framework to increase our understanding about the predictability of species persistence within multispecies communities.
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Affiliation(s)
- Chuliang Song
- Department of Civil and Environmental Engineering, MIT, Cambridge, MA, USA.,Department of Biology, McGill University, Montreal, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Lawrence H Uricchio
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | | | - Serguei Saavedra
- Department of Civil and Environmental Engineering, MIT, Cambridge, MA, USA
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18
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Deng J, Angulo MT, Saavedra S. Generalizing game-changing species across microbial communities. ISME COMMUNICATIONS 2021; 1:22. [PMID: 36737668 PMCID: PMC9723773 DOI: 10.1038/s43705-021-00022-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/10/2021] [Accepted: 05/18/2021] [Indexed: 02/07/2023]
Abstract
Microbes form multispecies communities that play essential roles in our environment and health. Not surprisingly, there is an increasing need for understanding if certain invader species will modify a given microbial community, producing either a desired or undesired change in the observed collection of resident species. However, the complex interactions that species can establish between each other and the diverse external factors underlying their dynamics have made constructing such understanding context-specific. Here we integrate tractable theoretical systems with tractable experimental systems to find general conditions under which non-resident species can change the collection of resident communities-game-changing species. We show that non-resident colonizers are more likely to be game-changers than transients, whereas game-changers are more likely to suppress than to promote resident species. Importantly, we find general heuristic rules for game-changers under controlled environments by integrating mutual invasibility theory with in vitro experimental systems, and general heuristic rules under changing environments by integrating structuralist theory with in vivo experimental systems. Despite the strong context-dependency of microbial communities, our work shows that under an appropriate integration of tractable theoretical and experimental systems, it is possible to unveil regularities that can then be potentially extended to understand the behavior of complex natural communities.
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Affiliation(s)
- Jie Deng
- Department of Civil and Environmental Engineering, MIT, Cambridge, MA, USA
| | - Marco Tulio Angulo
- CONACyT - Institute of Mathematics, Universidad Nacional Autónoma de México, Juriquilla, México.
| | - Serguei Saavedra
- Department of Civil and Environmental Engineering, MIT, Cambridge, MA, USA.
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19
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Coexistence holes characterize the assembly and disassembly of multispecies systems. Nat Ecol Evol 2021; 5:1091-1101. [PMID: 34045718 DOI: 10.1038/s41559-021-01462-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 04/07/2021] [Indexed: 11/08/2022]
Abstract
A central goal of ecological research has been to understand the limits on the maximum number of species that can coexist under given constraints. However, we know little about the assembly and disassembly processes under which a community can reach such a maximum number, or whether this number is in fact attainable in practice. This limitation is partly due to the challenge of performing experimental work and partly due to the lack of a formalism under which one can systematically study such processes. Here, we introduce a formalism based on algebraic topology and homology theory to study the space of species coexistence formed by a given pool of species. We show that this space is characterized by ubiquitous discontinuities that we call coexistence holes (that is, empty spaces surrounded by filled space). Using theoretical and experimental systems, we provide direct evidence showing that these coexistence holes do not occur arbitrarily-their diversity is constrained by the internal structure of species interactions and their frequency can be explained by the external factors acting on these systems. Our work suggests that the assembly and disassembly of ecological systems is a discontinuous process that tends to obey regularities.
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20
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Van Goor J, Piatscheck F, Houston DD, Nason JD. Differential effects of nematode infection on pollinating and non-pollinating fig wasps: Can shared antagonism provide net benefits to a mutualism? J Anim Ecol 2021; 90:1764-1775. [PMID: 33934356 DOI: 10.1111/1365-2656.13495] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 04/01/2021] [Indexed: 01/12/2023]
Abstract
Species pairs that form mutualistic associations are also components of broader organismal community networks. These interaction networks have shaped the evolution of individual mutualisms through interspecific interactions ranging from secondarily mutualistic to intensely antagonistic. Our understanding of this complex context remains limited because characterizing the impacts of species interacting with focal mutualists is often difficult. How is the fitness of mutualists impacted by the co-occurring interactive network of community associates? We investigated this context using a model interaction network comprised of a fig and fig wasp mutualist, eight non-pollinating fig wasp (NPFW) antagonists/commensals and a nematode previously believed to be associated only with the pollinator wasp mutualist. Through repeated sampling and field observations, we characterized the ecological roles of these mutualist-associated organisms to identify key antagonists. We then investigated how potential nematode infection of NPFWs could impact wasp survival across key life stages and, in turn, inferred how this influences the fitness of the fig-pollinator mutualists. Unexpectedly, we found all Ficus petiolaris-associated NPFWs to be the targets for nematode infection, with infection levels sometimes exceeding that of pollinators. Experimental data collected for the most abundant NPFW species suggest that nematode infection significantly reduces their longevity. Further, comparisons of nematode loads for emerging and successfully arriving NPFWs suggest that infection severely limits their dispersal ability. Through these observations, we conclude that this infection could impact NPFWs more severely than either mutualistic partner, suggesting a novel role of density-dependent facultative mutualism between figs, pollinator wasps and the nematode. This antagonist-mediated suppression of other network antagonists may present an ecologically common mechanism through which antagonists can present net benefits for mutualists' fitness.
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Affiliation(s)
- Justin Van Goor
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA.,Department of Biology, University of Maryland College Park, College Park, MD, USA
| | - Finn Piatscheck
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA.,Smithsonian Tropical Research Institute, Panamá, República de Panamá
| | - Derek D Houston
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA.,Department of Natural and Environmental Sciences, Western Colorado University, Gunnison, CO, USA
| | - John D Nason
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
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21
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Song C, Saavedra S. Bridging parametric and nonparametric measures of species interactions unveils new insights of non‐equilibrium dynamics. OIKOS 2021. [DOI: 10.1111/oik.08060] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Chuliang Song
- Dept of Biology, McGill Univ. Montreal Canada
- Dept of Ecology and Evolutionary Biology, Univ. of Toronto Toronto Canada
| | - Serguei Saavedra
- Dept of Civil and Environmental Engineering, MIT Cambridge MA USA
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22
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Experimental evidence of the importance of multitrophic structure for species persistence. Proc Natl Acad Sci U S A 2021; 118:2023872118. [PMID: 33727421 DOI: 10.1073/pnas.2023872118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ecological theory predicts that species interactions embedded in multitrophic networks shape the opportunities for species to persist. However, the lack of experimental support of this prediction has limited our understanding of how species interactions occurring within and across trophic levels simultaneously regulate the maintenance of biodiversity. Here, we integrate a mathematical approach and detailed experiments in plant-pollinator communities to demonstrate the need to jointly account for species interactions within and across trophic levels when estimating the ability of species to persist. Within the plant trophic level, we show that the persistence probability of plant species increases when introducing the effects of plant-pollinator interactions. Across trophic levels, we show that the persistence probabilities of both plants and pollinators exhibit idiosyncratic changes when experimentally manipulating the multitrophic structure. Importantly, these idiosyncratic effects are not recovered by traditional simulations. Our work provides tractable experimental and theoretical platforms upon which it is possible to investigate the multitrophic factors affecting species persistence in ecological communities.
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23
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Medeiros LP, Song C, Saavedra S. Merging dynamical and structural indicators to measure resilience in multispecies systems. J Anim Ecol 2021; 90:2027-2040. [PMID: 33448053 DOI: 10.1111/1365-2656.13421] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/09/2020] [Indexed: 11/30/2022]
Abstract
Resilience is broadly understood as the ability of an ecological system to resist and recover from perturbations acting on species abundances and on the system's structure. However, one of the main problems in assessing resilience is to understand the extent to which measures of recovery and resistance provide complementary information about a system. While recovery from abundance perturbations has a strong tradition under the analysis of dynamical stability, it is unclear whether this same formalism can be used to measure resistance to structural perturbations (e.g. perturbations to model parameters). Here, we provide a framework grounded on dynamical and structural stability in Lotka-Volterra systems to link recovery from small perturbations on species abundances (i.e. dynamical indicators) with resistance to parameter perturbations of any magnitude (i.e. structural indicators). We use theoretical and experimental multispecies systems to show that the faster the recovery from abundance perturbations, the higher the resistance to parameter perturbations. We first use theoretical systems to show that the return rate along the slowest direction after a small random abundance perturbation (what we call full recovery) is negatively correlated with the largest random parameter perturbation that a system can withstand before losing any species (what we call full resistance). We also show that the return rate along the second fastest direction after a small random abundance perturbation (what we call partial recovery) is negatively correlated with the largest random parameter perturbation that a system can withstand before at most one species survives (what we call partial resistance). Then, we use a dataset of experimental microbial systems to confirm our theoretical expectations and to demonstrate that full and partial components of resilience are complementary. Our findings reveal that we can obtain the same level of information about resilience by measuring either a dynamical (i.e. recovery) or a structural (i.e. resistance) indicator. Irrespective of the chosen indicator (dynamical or structural), our results show that we can obtain additional information by separating the indicator into its full and partial components. We believe these results can motivate new theoretical approaches and empirical analyses to increase our understanding about risk in ecological systems.
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Affiliation(s)
- Lucas P Medeiros
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Chuliang Song
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Biology, Quebec Centre for Biodiversity Science, McGill University, Montreal, Quebec, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Serguei Saavedra
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
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24
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Medeiros LP, Boege K, Del-Val E, Zaldívar-Riverón A, Saavedra S. Observed Ecological Communities Are Formed by Species Combinations That Are among the Most Likely to Persist under Changing Environments. Am Nat 2021; 197:E17-E29. [PMID: 33417517 DOI: 10.1086/711663] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractDespite the rich biodiversity found in nature, it is unclear to what extent some combinations of interacting species, while conceivable in a given place and time, may never be realized. Yet solving this problem is important for understanding the role of randomness and predictability in the assembly of ecological communities. Here we show that the specific combinations of interacting species that emerge from the ecological dynamics within regional species pools are not all equally likely to be seen; rather, they are among the most likely to persist under changing environments. First, we use niche-based competition matrices and Lotka-Volterra models to demonstrate that realized combinations of interacting species are more likely to persist under random parameter perturbations than the majority of potential combinations with the same number of species that could have been formed from the regional pool. We then corroborate our theoretical results using a 10-year observational study, recording 88 plant-herbivore communities across three different forest successional stages. By inferring and validating plant-mediated communities of competing herbivore species, we find that observed combinations of herbivores have an expected probability of species persistence higher than half of all potential combinations. Our findings open up the opportunity to establish a formal probabilistic and predictive understanding of the composition of ecological communities.
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25
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Saavedra S, Medeiros LP, AlAdwani M. Structural forecasting of species persistence under changing environments. Ecol Lett 2020; 23:1511-1521. [PMID: 32776667 DOI: 10.1111/ele.13582] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 06/07/2020] [Accepted: 07/08/2020] [Indexed: 12/15/2022]
Abstract
The persistence of a species in a given place not only depends on its intrinsic capacity to consume and transform resources into offspring, but also on how changing environmental conditions affect its growth rate. However, the complexity of factors has typically taken us to choose between understanding and predicting the persistence of species. To tackle this limitation, we propose a probabilistic approach rooted on the statistical concepts of ensemble theory applied to statistical mechanics and on the mathematical concepts of structural stability applied to population dynamics models - what we call structural forecasting. We show how this new approach allows us to estimate a probability of persistence for single species in local communities; to understand and interpret this probability conditional on the information we have concerning a system; and to provide out-of-sample predictions of species persistence as good as the best experimental approaches without the need of extensive amounts of data.
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Affiliation(s)
- Serguei Saavedra
- Department of Civil and Environmental Engineering, MIT, 77 Massachusetts Av, 02139, Cambridge, MA, USA
| | - Lucas P Medeiros
- Department of Civil and Environmental Engineering, MIT, 77 Massachusetts Av, 02139, Cambridge, MA, USA
| | - Mohammad AlAdwani
- Department of Civil and Environmental Engineering, MIT, 77 Massachusetts Av, 02139, Cambridge, MA, USA
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26
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Tabi A, Pennekamp F, Altermatt F, Alther R, Fronhofer EA, Horgan K, Mächler E, Pontarp M, Petchey OL, Saavedra S. Species multidimensional effects explain idiosyncratic responses of communities to environmental change. Nat Ecol Evol 2020; 4:1036-1043. [PMID: 32572220 DOI: 10.1038/s41559-020-1206-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 04/15/2020] [Indexed: 01/30/2023]
Abstract
Environmental change can alter species' abundances within communities consistently; for example, increasing all abundances by the same percentage, or more idiosyncratically. Here, we show how comparing effects of temperature on species grown in isolation and when grown together helps our understanding of how ecological communities more generally respond to environmental change. In particular, we find that the shape of the feasibility domain (the parameter space of carrying capacities compatible with positive species' abundances) helps to explain the composition of experimental microbial communities under changing environmental conditions. First, we introduce a measure to quantify the asymmetry of a community's feasibility domain using the column vectors of the corresponding interaction matrix. These column vectors describe the effects each species has on all other species in the community (hereafter referred to as species' multidimensional effects). We show that as the asymmetry of the feasibility domain increases the relationship between species' abundance when grown together and when grown in isolation weakens. We then show that microbial communities experiencing different temperature environments exhibit patterns consistent with this theory. Specifically, communities at warmer temperatures show relatively more asymmetry; thus, the idiosyncrasy of responses is higher compared with that in communities at cooler temperatures. These results suggest that while species' interactions are typically defined at the pairwise level, multispecies dynamics can be better understood by focusing on the effects of these interactions at the community level.
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Affiliation(s)
- Andrea Tabi
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.
| | - Frank Pennekamp
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Florian Altermatt
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Roman Alther
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Emanuel A Fronhofer
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.,ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Katherine Horgan
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Elvira Mächler
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Mikael Pontarp
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Owen L Petchey
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Serguei Saavedra
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
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27
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Spaak JW, De Laender F. Intuitive and broadly applicable definitions of niche and fitness differences. Ecol Lett 2020; 23:1117-1128. [DOI: 10.1111/ele.13511] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/14/2020] [Accepted: 03/18/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Jurg W. Spaak
- University of Namur Institute of Life‐Earth‐Environment Namur Center for Complex Systems Namur Rue de Bruxelles 61 Belgium
| | - Frederik De Laender
- University of Namur Institute of Life‐Earth‐Environment Namur Center for Complex Systems Namur Rue de Bruxelles 61 Belgium
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28
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Song C, Saavedra S. Telling ecological networks apart by their structure: An environment-dependent approach. PLoS Comput Biol 2020; 16:e1007787. [PMID: 32324730 PMCID: PMC7200011 DOI: 10.1371/journal.pcbi.1007787] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 05/05/2020] [Accepted: 03/11/2020] [Indexed: 11/20/2022] Open
Abstract
The network architecture of an ecological community describes the structure of species interactions established in a given place and time. It has been suggested that this architecture presents unique features for each type of ecological interaction: e.g., nested and modular architectures would correspond to mutualistic and antagonistic interactions, respectively. Recently, Michalska-Smith and Allesina (2019) proposed a computational challenge to test whether it is indeed possible to differentiate ecological interactions based on network architecture. Contrary to the expectation, they found that this differentiation is practically impossible, moving the question to why it is not possible to differentiate ecological interactions based on their network architecture alone. Here, we show that this differentiation becomes possible by adding the local environmental information where the networks were sampled. We show that this can be explained by the fact that environmental conditions are a confounder of ecological interactions and network architecture. That is, the lack of association between network architecture and type of ecological interactions changes by conditioning on the local environmental conditions. Additionally, we find that environmental conditions are linked to the stability of ecological networks, but the direction of this effect depends on the type of interaction network. This suggests that the association between ecological interactions and network architectures exists, but cannot be fully understood without attention to the environmental conditions acting upon them. It has been suggested that different types of species interactions lead to ecological networks with different architectures. For example, mutualistic and antagonistic interaction networks have been shown to have nested and modular architectures, respectively. Importantly, this differentiation can provide clues about the link between the dynamics and structures shaping ecological communities. Recently, Michalska-Smith and Allesina (2019) turned this assumption into a serious computational challenge for the scientific community. Here, we embrace this challenge. We confirm that network architecture alone is not enough to differentiate interaction networks. However, we show that network architectures can differentiate between mutualistic and antagonistic interaction networks by using information about their local environmental conditions. In other words, ignoring environmental information throws out the predictable patterns of network architectures along environmental gradients. Thus, this response is also a reminder that ecological networks may only make sense in the light of environmental information.
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Affiliation(s)
- Chuliang Song
- Department of Civil and Environmental Engineering, MIT, Cambridge, Massachusetts, United States of America
- * E-mail:
| | - Serguei Saavedra
- Department of Civil and Environmental Engineering, MIT, Cambridge, Massachusetts, United States of America
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